Benzene multiple toxicities

The e. posure route partly determines the distribution of the chemical in die body. Like tlie chemical benzene, a single chemical may follow multiple routes of e. posure. The liver, like the skin, acts as a filter. The liver is the primary dcto.xification site. To.xicants that arc absorbed into the lungs, skin, mouth, and esophagus may temporarily bypass the liver however, toxicants absorbed tluougli the stomach and intestines follow the blood s direct path to tlie liver. 

Developmental Toxicity. Based on epidemiological studies at hazardous waste sites, an increased susceptibility to benzene of pregnant women or their offspring has not been demonstrated (Budnick et al. 1984 Goldman et al. 1985 Heath 1983 Olsen 1983). However, these studies have several limitations that make it impossible to assess the effect of benzene on the human fetus. For example, the few studies that do exist are limited by a lack of control incidences for end points, problems in identifying exposed populations, a lack of data on exposure levels, and/or exposure to multiple substances (Budnick et al. 

Polyaromatic hydrocarbons (PAHs) — The most common smaller and more volatile compounds found in oil. They contain multiple benzene rings. Crude oils and residual oils contain varying amounts of these compounds, some of which may be toxic to humans and aquatic life. 

The multiple linear equations given in TABLE 3 indicate a significant relationship of the observed toxicities with several physico-chemical characteristics of these compounds. However, only some 60% of the total variation is explained by equation 3d and the corresponding standard error of the estimate, s = 0.60 is quite large. This means that for a number of compounds the predicted toxic concentrations differ by more than one order of magnitude from those observed experimentally. As there is a spread of close to five orders of magnitude between the molar concentrations of the least and most toxic compounds, the predictive capacity of equation 3d is still of value, though somewhat limited in applicability. This fact stimulates the desire for a closer inspection of the data with a view to delineate more precise relationships for smaller, more easily defined subsets of mono-substituted benzene derivatives. 

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